Related topics: volcanic ash · earthquake · nasa · satellite · glaciers

Tree rings could pin down Thera volcano eruption date

Charlotte Pearson's eyes scanned a palm-sized chunk of ancient tree. They settled on a ring that looked "unusually light," and she made a note without giving it a second thought. Three years later, and armed with new methodology ...

Indonesian volcano spews massive ash cloud

Indonesia's most active volcano Mount Merapi erupted Friday, shooting a column of ash some 5,000 metres (16,000 feet) into the air in its second major eruption this month.

Scientists quantify how wave power drives coastal erosion

Over millions of years, Hawaiian volcanoes have formed a chain of volcanic islands stretching across the Northern Pacific, where ocean waves from every direction, stirred up by distant storms or carried in on tradewinds, ...

Erupting Indonesian volcano spews ash, lava

Indonesia's Mount Merapi, one of the world's most active volcanoes, erupted Thursday as fiery red molten lava streamed down from the crater and it belched clouds of grey ash 2,000 metres (6,500 feet) into the sky.

Icelandic volcano swell signals potential eruption

Small earthquakes and a so-called "inflation" of the mountain, signalling a potential volcanic eruption, have been reported near Iceland's famous "Blue Lagoon," local authorities said Monday.

Philippine volcano alert lowered, thousands return home

Philippine authorities on Sunday lowered the alert level at Taal Volcano, two weeks after it began spewing ash, steam and rocks, a move that will allow many of the more than 376,000 displaced villagers to return home.

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Volcano

A volcano is an opening, or rupture, in a planet's surface or crust, which allows hot, molten rock, ash, and gases to escape from below the surface. Volcanic activity involving the extrusion of rock tends to form mountains or features like mountains over a period of time. The word volcano is derived from the name of Vulcano island off Sicily. In turn, it was named after Vulcan, the Roman god of fire.

Volcanoes are generally found where tectonic plates are diverging or converging. A mid-oceanic ridge, for example the Mid-Atlantic Ridge, has examples of volcanoes caused by divergent tectonic plates pulling apart; the Pacific Ring of Fire has examples of volcanoes caused by convergent tectonic plates coming together. By contrast, volcanoes are usually not created where two tectonic plates slide past one another. Volcanoes can also form where there is stretching and thinning of the Earth's crust (called "non-hotspot intraplate volcanism"), such as in the African Rift Valley, the Wells Gray-Clearwater volcanic field and the Rio Grande Rift in North America and the European Rhine Graben with its Eifel volcanoes.

Volcanoes can be caused by mantle plumes. These so-called hotspots, for example at Hawaii, can occur far from plate boundaries. Hotspot volcanoes are also found elsewhere in the solar system, especially on rocky planets and moons.

This text uses material from Wikipedia, licensed under CC BY-SA